As noted, it's a legal connection. It's also very doable, though boarding will have started by the time you land if both flights are on time.

However, my recollection is that those hub-LAX flights just before the LAX-SYD flight may each have 20 or more passengers connecting to the SYD flight, so you won't be the only one making the connection by a long shot. I've had the SYD flight held for quite a while (more than an hour) for connecting passengers. It's also frequently held due to light headwinds (since the plane can't land in SYD before 6:00 due to the SYD curfew). So I think that your odds of making the SYD flight are actually quite good with that 35 minute connection.

LAX is small, so even if the SYD flight isn't held, you likely won't have a long walk. Worst case is your DTW-LAX flight arrives at T6 (reasonably likely if it's a 763) and the SYD flight is out of T5, which is a 10 minute walk. There won't be time for a shower and leisurely stop in the Sky Club (or possibly even a bathroom stop in the terminal bathrooms), of course.